If you're an American and you're not having fun, it just might be your own fault. Our long national expedition is entering its 238th year, and from the start, it was clear that this would be a bracing place to live. There would be plenty of food, plenty of land, plenty of minerals in the mountains and timber in the wilderness. You might have to work hard, but you'd have a grand time doing it.

That promise, for the most part, has been kept. There would be land rushes and gold rushes and wagon trains and riverboats and cities built hard against cities until there was no place to build but up, so we went in that direction too. We created outrageous things just because we could--the Hoover Dam, the Golden Gate Bridge, the Empire State Building, which started to rise the year after the stock market crashed, because what better way to respond to a global economic crisis than to build the world's tallest skyscraper? We got to the moon 40 years later and, true to our hot-rodding spirit, soon contrived to get a car up there as well. The tire tracks left on the lunar surface (tracks that are still there) are the real American graffiti.

All human beings may come equipped with the pursuit-of-happiness impulse--the urge to find lusher land just over the hill, fatter buffalo in the next valley--but it's Americans who have codified the idea, written it into the Declaration of Independence and made it a central mandate of the national character. American happiness would never be about savor-the-moment contentment. That way lay the reflective café culture of the Old World--fine for Europe, not for Jamestown. Our happiness would be bred, instead, of an almost adolescent restlessness, an itch to do the Next Big Thing. The terms of the deal the founders offered are not easy: there's no guarantee that we'll actually achieve happiness, but we can go after it in almost any way we choose. All by itself, that freedom ought to bring us joy, but the more cramped, distracted, maddeningly kinetic nature of the modern world has made it harder than ever. Somehow there must be a way to thread that needle, to reconcile the contradictions between our pioneer impulses and our contemporary selves.

Those impulses are very deeply rooted: pilgrims to the New World were a self-selected group. Not every person suffering under the whip of tyranny or the crush of poverty had the temperamental wherewithal to pick up, pack up and travel to the other side of the globe and start over. Those who did were looking for something--pursuing something--and happiness is as good a way of defining that goal as any. Once that migrant population started raising babies on a new continent, the odds were that the same questing spirit would be bred into or at least taught to the new generations as well.

And it has been. It took us 100 years to settle the continent and less than 200 to become the world's dominant power. We snatched and grabbed and extracted, yes, but we gave back too. Happy people don't just accumulate fortune; they invent things--the lightbulb, the telegraph, the movie camera, the airplane, the mass-produced automobile, the polio vaccine, the personal computer, social media, the iPhone. And happy people are also generous people, rebuilding other nations (hello, Marshall Plan) and donating to charities; the U.S. still ranks No. 1 among all nations in per capita charitable giving.